Method and apparatus for processing yarn



R. c. SPURGEON 3,377,672

METHOD AND APPARATUS FOR PROCESSING YARN April 16, 1968 Filed 001.. 21, 1966 5 Sheets-Sheet 1 FIG:1

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April 16, 1968 R. c. SPURGEON 7 METHOD AND APPARATUS FOR PROCESSING YARN Filed Oct. 21, 1966 3 Sheets-Sheet 2 INVENTOR. filt'fidid (15 0 2012, BY

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April 16, 1968 R- C SPURGEON 3,377,672

METHOD AND APPARATUS FOR PROCESSING YARN Filed 001. 21, 1966 5 Sheets-Sheet 5 '1 N i a S FIG. 5

N Q A v INVENTOR.

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United States Patent 13 Ciainrs. (Ci. 28-4) ABSTRACT 015' THE DESQLGSURE In one form of the apparatus, a yarn package, tension leveling device, yarn tensioning device, heater and utility are arranged serially, in the order named. In another form, a yarn package, a tension leveling device, heater, tension reducing device and utility are arranged serially in the order named. In either case, the utility draws yarn from the package as required by the work it is doing, and as the yarn leaves the heater, it passes over a knife edge, which results in the yarn path being turned sharp- 1y. In the second form of the apparatus, the tension reducing device functions to reduce yarn tension between the knife edge and the utility.

This invention relates to yarns having an elastic nature and to methods of and apparatus for processing such yarns.

This application is a continuation-in-part of my copending application, Ser. No. 480,951, filed Aug. 19, 1965, which in turn is a continuation-in-part of my copending application, Ser. No. 405,440, filed Oct. 21, 1964 now U.S. Patent 3,323,753, granted June 6, 1967.

It is well known in the art that passing a thermoplastic yarn under tension through a linear path having a sharply angular portion imparts a more or less permanent tendency to curl to the yarn if it is at an elevated temperature at the time is passes through the angular portion of the yarn path. 1

The filaments of the elasticized yarn are cha acterized by a coiled appearance when in an untensioned condition and in most instances have a slightly flattened cross section. The coils or loops are generally relatively small in number and large in amplitude. They are generally of random sizes, but on occasion yarn is found in t which all of the loops appear to be of substantially constant size.

If the yarn initially is free of torsional stresses and if no torsional stresses are deliberately introduced during processing, the loops appear in groups, with the loops of alternate groups running in one direction and the loops of intervening groups running in the opposite direction. In some instances the loops will run in the same direction for as much as several inches before reversing their direction. There is no overall tendency for the yarn to twist when the loops are removed by tensioning the yarn.

Conventional elasticized yarns of the type just described have not proved to be entirely satisfactory because of the frequent appearance of dead spots, i.e., places in the yarn where the yarn does not curl, or places in the yarn where the yarn has a helican configuration that is permanently lost when the yarn is pulled straight. A dead spot may develop when the cross-sectional area of the fiber is not uniform, i.e., when a differential lengthening or shortening of the fiber occurs. A differential lengthening or shortening of the fiber may be due to improper heating of the fiber. More often, however, it is due to variations in tension in the yarn between the yarn tensioning device and the yarn take-11p device or other utility. Conventional yarn tensioning devices operate to control the level of yarn tension, but inevitably the yarn tension varies from that desired, sometimes rising above the desired yarn tension and sometimes falling below the desired yarn tension. When this happens, the cross-sectional area of the yarn passing through the angular portion of the yarn path changes and differential longitudinal stresses de velop, in consequence of which a dead spot may appear in the yarn. Accordingly, an important object of the pres ent invention is to provide an improved edge crimped, elasticized thermoplastic yarn, i.e., one free of dead spots or having a high crimp curliness which is permanent throughout the length of the yarn, by leveling the yarn tension in the yarn passing through the angular portion of the yarn path.

Another object is to provide such a yarn having greater bulk, stretchability and insulating properties and a better hand than conventional edge crimped, elasticized thermo. plastic yarn.

Another object is to provide a method and apparatus for processing such yarn at a high rate.

Another object is to provide a method and apparatus for processing such yarn whereby the yarn produced during the start-up period, as well as the yarn produced after the start-up period, is superior in quality.

Another object is to produce such yarn at a high rate and immediately thereafter feed it directly to a utility.

Another object is to produce such yarn at a high rate and immediately thereafter reduce the level of yarn tension preliminary to feeding the yarn directly to a utility.

Other objects of the invention will. become apparent when the following description is read with reference to the accompanying drawings, wherein:

FIGURE 1 is an elevation of a tension control mechanism constructed in accordance with the invention;

FIGURE 2 is a perspective view of a yarn heating device constructed in accordance with the invention;

FIGURE 3 is a perspective view of the rear end of the heating device shown in FIGURE 2;

FIGURE 4 is an enlarged section on line IV-IV in FIGURE 2; and

FIGURE 5 is an elevation diagrammatically showing a modified arrangement of apparatus constructed in accordance with the invention.

Referring particularly to FIGURE 11, the tension control mechanism comprises a horizontally extending base 10 mounting a yarn tension device 12 and a yarn tension leveling device 14. At one end of the base is an eyelet 18 carried by a horizontal arm 20 extending from an upright post 22. The yarn tension leveling device 14 includes a roller 24 covered with shell cordovan leather.

To the right of the roller 24 is a ring 24 embracing an upright standard 28 which carries an eyelet 30 at the head thereof. The yarn tension device l2 includes an eyelet 32, a set of rings 34, a set of rings and an eyelet 36, aligned as shown. Reference may be had to my copending application Ser. No. 405,440, filed Oct. 21, 1964, for a full and detailed description of the tension control mechanism and its operation.

Referring particularly to FIGURES 2, 3 and 4, the heater illustrated, generally designated 37, comprises a jacket 38 of insulating material covering the body of the heater, designated 39. The heater basically is the same as that disclosed in my copending application Ser. No. 318,688, filed Oct. 24, 1963, now abandoned, to which reference may be had for further details. At the fore end of the heater is a plate 40 which carries a pair of eyelets 42 and 44. At the rear end of the heater is a plate as which carries a pair of eyelets 4S and 50. Overlying the plate 40 is another plate 52 which is adjustable and is secured in position by means of a screw 54. Screws 55 secure an adjustable blade 56 in position on plate 52, which blade 56 is provided with a knife edge 58.

Uncrirnped yarn, designated 16, drawn from a source not shown, is threaded through the eyelet 18, passed under the roller 24 of the tension leveling device 14 and threaded through the ring 26 and eyelet 30. Then it is threaded through the eyelet 32, the several rings 34 and 35 and eyelet 36 of the yarn tension device 12. The yarn 16 issuing from the eyelet 36 is then threaded through the eyelet 42, passed rearwardly through the heater and threaded through the eyelet 48, whereupon it is turned back upon itself, threaded through the eyelet 50, passed forwardly through the heater and threaded through the eyelet 44. As it issues from the eyelet 44, it turns downwardly, as shown, in FIGURE 4, to pass under the knife edge 58 in contact therewith. Then it extends upwardly again directly to a take-up spool or other utility, e.g., a knitting machine (not shown).

The yarn to be elasticized according to the invention may satisfactorily comprise any continuous filamentary strand composed of an organic hydrophobic, thermoplastic fiber material. However, nylon yarns are preferred since they give a higher degree of elastization than other types of yarns. Yarn wherein the filaments have a generally circular cross-section and a smooth surface are most readily employed and give the most satisfactory results. The denier and filament size of the yarn to be processed may vary within wide limits and almost any of the commercially available yarns within the previously specified class can be satisfactorily employed.

In the type of apparatus described, the yarn is forced through an abrupt change of direction by passing it under a knife edge, but it will be apparent that the yarn may be caused to undergo the required abrupt change of direction in other ways.

Although the apparatus for producing the yarn is relatively simple, there are several variables which affect the nature of the yarn produced. For example, the radius of curvature of the knife edge, the tension in the yarn passed under the blade, the temperature of the heater element, the rate of cooling the yarn after it passes the knife edge and the linear velocity of the yarn can all have their effect upon the nature of the yarn produced.

The radius of curvature of the knife edge can vary within wide limits, but it is preferably as small as possible without severing the yarn. The angle of approach and the angle of departure of the yarn to the blade may also vary within limits, although the total of these two angles should be less than about 120 degrees and preferably less than 100 degrees. Operative limits for the tension in the yarn following its contact with the knife edge vary depending upon a number of factors including the temperature of the yarn and the type of yarn being employed, but as a general rule, the operative range extends from about .05 grams per denier to approximately 1 gram per denier with the preferred range being from about .1 to .4 gram per denier. The linear velocity of the yarn under the knife edge may also vary within wide limits depending upon the temperature of the heater, the length of the heater, the distance of the heater from the knife edge and the type of yarn being passed under the blade. As a general rule, it may be stated that the operable range for the linear velocity of the yarn through the heater and under the knife edge has no upper limit of yards per minute, the preferred range having an upper limit of approximately 800 yards per minute. Although the distance of the knife edge from the heater may vary within reasonable limits, as a general rule, it is preferred that the knife edge be placed as close to the heater as possible.

Preferably the yarn is allowed to cool under tension after its passage under the knife blade. The stresses in the yarn are then released by reheating the yarn under such conditions as to permit it to assume a distorted linear configuration, and this second heating operation fully develops the elastic nature of the yarn.

The full elastic nature of the elasticized yarn may be developed after the yarn is formed into fabrics. In this event, the yarn may be passed from the knife edge directly to means which knits or waeaves it into fabric. The fabrics are then subjected to the second heating operation.

During the start-up period, yarn travel increases from zero to approximately 800 yards per minute. Yarn produced in accordance with the invention is commercially acceptable whether or not produced during the start-up eriod, so long as the tension control mechanism, and particularly the tension leveling device, is operating and so long as the heat is sufiicient.

Referring to FIGURE 5, the modified arrangement of apparatus constructed in accordance with the invention essentially is similar to that already described, except for the omission of tension device 12 and the addition of a tension reducing device, The apparatus includes a tension leveling device 110, a heater 112 and a tension reducing device 114.

The tension leveling device includes a roller 116. To the left of the roller 116 is a ring 118 embracing an upright standard 120 which carries an eyelet 122 at the head thereof, and to the right of the roller 116 is a ring 124 embracing an upright standard 126 which carries an eyelet 128 at the head thereof. Reference may be had to my copending application, Ser. No. 405,440, filed Oct. 21, 1964, for a description of the essential features of the tension leveling device.

The heater 112, similar to the heater 37, described hereinbefore, includes eyelets 130 and 132 at the lower end thereof and eyelets 134 and 136 at the upper end thereof. A blade 133 provided with a knife edge is mounted upon the lower end of the heater 112. The blade 138 is similar to the blade 56, described hereinbefore, and is mounted upon the heater 112 in a manner similar to the mounting of the blade 56 upon the heater 37.

To the right of the knife edge 140 is a standard 142 mounting an eyelet 144 at the head thereof.

The tension reducing device 114, disposed to the right of the standard 142, includes a roller 146 with a covering of polyurethane. Means (not shown) is provided for rotating the roller 146 in yarn advancing direction at a surface speed in excess of the linear speed of the yarn. Overlying the roller 146 is a member 143 of inverted U-shape. The extremities of the member 148 respectively mount eyelets 150 and 152. The member 148 is mounted upon the lower extremity of a rod 154, which extends upwardly through the coil of a stationarily mounted solenoid 156. The upper end of the rod 154 is connected to a tension spring 158. The coil of the solenoid being energized, the rod 154 is held in the position shown, against the influence of the spring 158.

Uncrimped yarn, designated 160, drawn from a source not shown, is threaded through the eyelet 122, passed downwardly along the standard 129 and threaded through the eyelet 118. Then it is passed under the roller 116 in contact therewith, threaded through the ring 124, passed upwardly along the standard 126 and threaded through the eyelet 128. Next, the yarn 150 is passed through the eyelets 130, 134, 136 and 132 of the heater 112. When the yarn issues from the eyelet 132 it is trained over the edge 140 of the blade 138, from whence it is passed through the eyelets 144, 150 and 152 and directly to the utility (not shown). The roller 116 turns in yarn advancing direction at a speed which exceeds the linear speed of the yarn. Tension in the yarn is induced by resistance to movement of the yarn over the edge 140 of the blade 138. The yarn between the tension leveling device 11-0 and the utility will be predetermined in length for a desired yarn tension. When said length increases, the rings 118 and 124 are lowered, removing some of the yarn from engagement with the roller 116 and increasing slippage between the roller 116 and the yarn, Thus the amount of yarn passing under the roller 116 is reduced and the yarn between the tension leveling device and the utility is restored to its initial length. When said length decreases, the rings 118 and 124 are raised, causing a greater length of yarn to engage the roller 116 and decreasing slippage between the roller 116 and the yarn. Thus the amount of yarn passing under the roller 116 is increased and the length of yarn between the tension leveling device and the utility is restored to its initial length. The yarn tension on the downstream side of the edge 140 may be too high for the utility to which the yarn is being fed. Therefore, for best results, the yarn tension must be reduced just before the yarn reaches the utility. This reduction is effected by the roller 146, which, as noted hereinbefore, turns in yarn advancing direction at a surface speed in excess of the linear speed of the yarn. If it is not desired to reduce the tension, the solenoid is deenergized, whereupon the spring 158 raises the rod 154 and member 148 to a position for holding the yarn 160 out of contact with the roller 146.

The initial source of yarn 16 may be a package of the yarn-spun and drawn to the proper denier, but crimped. However, it will be noted that the apparatus and method of the invention may be employed during the manufacture of the yarn itself, either during the primary spinning stage or during the secondary draw twisting stage. Preferably, when employed during the primary spinning stage, i.e., after spinning, but before drawing to proper denier, the undra-wn filaments pass from the spinnerette to a cooling stack and then over a godet before being treated in accordance with the invention.

When compared with conventional edge crimped yarn, the yarn produced by the apparatus and method of the invention has an improved wool-like hand, In addition, it has a high crimp curliness which is permanent throughout the entire length of the yarn, i.e., it is free of dead spots. It has a higher bulkiness, which, of course, favors garments lighter in weight and made of less yarn. Furthermore, it has definitely enhanced stretchability.

What is claimed is:

1. In a method of crimping a continuous filament ther moplastic yarn, the steps comprising drawing uncrimped continuous filament thermoplastic yarn from a source to a utility thereof freely across a sharp edge disposed at the apex of an angle formed between the path of delivery of said yarn to said edge and the path of withdrawal of said yarn from said edge, restraining said yarn to hold it against said edge and to induce predetermined tension in said yarn when a predetermined length of said yarn extends from said utility to a location upstream of said edge, compensating for variations in the length of the yarn extending from said utility to said location whereby to maintain the same uniform, and heating the yarn so that at least a portion thereof in contact with said edge is at a temperature sufiicient to plasticize but insufiicient to melt said yarn.

2. The method according to claim 1 wherein compensation for variations in the length of the yarn extending from the utility to the location upstream of the edge is effected by training said yarn about a roller with a certain length thereof engaging said roller when the length of the yarn extending from said utility to said location corresponds to the predetermined length, rotating said roller in yarn advancing direction at a surface speed in excess of the linear speed of said yarn so that said roller continually slips relative to said yarn, automatically increasing the length of said yarn engaging said roller in response to a decrease in said predetermined length thereby to decrease slippage, and automatically decreasing the length of said yarn engaging said roller in response to an increase in said predetermined length thereby to increase slippage.

3. The method according to claim 1 wherein the yarn is crimped during the primary melt spinning stage of yarn manufacture.

4. The method according to claim 1 wherein the yarn is crimped durin the secondary draw twisting stages of yarn manufacture.

5. In a method of supplying a utility with crimped continuous filament thermoplastic yarn, the steps comprising drawing uncrirnped continuous filament thermoplastic yarn from a source thereof freely across a sharp edge disposed at the apex of an angle formed between the path of delivery of said yarn to said edge and the path of withdrawal of said yarn from said edge, restraining said yarn to hold it against said edge and to induce predetermined tension in said yarn when a predetermined length of said yarn extends from said utility to a location upstream of said edge, compensating for variations in the length of the yarn extending from said utility to said location whereby to maintain the same uniform, reducing the tension in the yarn on the downstream side of said edge to a desired level just before the yarn reaches said utility, and heating said yarn so that at least a portion thereof in contact with said edge is at a temperature sufficient to plasticize but insufficient to melt said yarn.

6. The method according to claim 5 wherein compensation for variations in the length of the yarn extending from the utility to the location upstream of the edge is effected by training said yarn about a roller with a certain length thereof engaging said roller when the length of the yarn extending from said utility to said location corresponds to the predetermined length, rotating said roller in yarn advancing direction at a surface speed in excess of the linear speed of said yarn so that said r0llercontinually slips relative to said yarn, automatically increasing the length of said yarn engaging said roller in response to a decrease in said predetermined length thereby to decrease slippage, and automatically decreasing the length of said yarn engaging said roller in response to an increase in said predetermined length thereby to increase slippage.

7. The method according to claim 5 wherein reduction in yarn tension to a desired level on the downstream side of the edge just before the yarn reaches the utility is effected by training said yarn about a roller, and rotating said roller in yarn advancing direction at a surface speed in excess of the linear speed of said yarn so that said roller continually slips relative to said yarn.

8. The method according to claim 5 wherein the yarn is crimped during the primary melt spinning stage of yarn manufacture.

9. The method according to claim 5 wherein the yarn is crimped during the secondary draw twisting stages of yarn manufacture.

10. The combination comprising a source of yarn, a utility operable at least periodically for continuously drawing yarn from said source, a sharp-edged blade, means for training said yarn over the edge of said blade, said edge being disposed at the apex of an angle formed between the path of delivery of said yarn to said edge and the path of withdrawal of said yarn from said edge, and tension leveling means between said yarn source and the edge of said blade, said edge being responsive to a predetermined yarn length between said tension leveling means and utility for developing resistance to movement of said yarn over the edge of said blade whereby to induce a predetermined tension in the yarn on the downstream side of said edge, and said tension level means being operative for maintaining the length of yarn betweeen said tension leveling means and utility uniform.

11. The combination defined in claim 10 wherein the means for training the yarn over the edge of the blade includes a heater on the upstream side of the blade operable for heating the yarn so that at least a portion thereof in contact with said edge is at a temperature sufiicient to plasticize but insufficient to melt said yarn.

12. The combination defined in claim 11 wherein the blade is stationarily mounted with its sharp edge close adjacent the point at which the yarn issues from the heater.

13. The combination defined in claim 12 wherein the blade is adjustably mounted directly upon the heater.

14. The combination defined in claim 10 wherein yarn tensioning means is disposed between the tension leveling means and the blade for coaction with the edge of said blade in the development of resistance to movement of said yarn over the edge of said blade and in the inducing of the predetermined tension in the yarn on the downstream side of said edge.

15. The combination defined in claim 10 wherein means operable for reducing the yarn tension is interposed between the blade and utility.

16. The combination defined in claim 15 wherein the tension reducing means comprises a roller, means for holding said yarn with a portion thereof engaging the surface of said roller, and means for rotating said roller in yarn advancing direction at :a rate such that the surface speed of said roller exceeds the linear speed of said yarn.

8 17. The combination defined in claim 16 wherein the face of the roller is of polyurethane.

18. The combination defined in claim 17 wherein the yarn holding means is operable for removing said yarn from contact with the surface of the roller.

References Cited UNITED STATES PATENTS 2,919,534 1/1960 Bolinger et al 281 X 3,028,653 4/1962 Evans 28-1 3,087,226 4/1963 Evans 28-72 3,137,912 6/1964 Preston et al 28-1 LOUIS K. RIMRODT, Primary Examiner. 

